The UK has signed a £65 million contract to build its first three Protector drones - the first UK-operated system capable of strike missions anywhere in the world.
General Atomics Aeronautical Systems will also build three control stations and support equipment as part of the deal.
In a statement, the Ministry of Defence (MOD) said the Protector is "a step-change" in the Royal Air Force's capability.
Defence Secretary Ben Wallace, who announced the contract at the virtual 2020 Air and Space Power Conference, said the Protector will help meet "the UK’s defence and security needs for decades to come".
"This aircraft will upgrade a whole range of lethal capabilities allowing us to control, protect and manage the battlespace from the air for hours on end," he said.
After a successful development phase, the Protector is set to enter service by mid-2024 and is the "world’s first certified" Remotely Piloted Air System (RPAS).
It means it will be able to fly in busy, unsegregated airspace, including civilian airspace, using its "ground-breaking 'detect and avoid' technology", the MOD said.
It could also be used to help civilian search and rescue operations, and disaster response missions.
The MOD said the Protector is able to "fly consistently for up to 40 hours", offering the Air Force "vastly improved armed intelligence and reconnaissance sorties".
The aircraft, equipped with anti-icing and lightning protection, comes with enhanced data links and "next-generation" strike weapons, including the Brimstone 3 missile.
It will replace the RAF's current Reaper RPAS force and will be deployed on Intelligence, Surveillance, Targeting and Reconnaissance (ISTAR) operations from its base at RAF Waddington, Lincolnshire.
The contract also includes an option to build 13 more aircraft and four ground control stations, which would complete the planned fleet of 16 aircraft and more than doubling the capability currently provided by Reaper.
Cover image: Protector at Creech Air Force Base in Nevada (Picture: RAF).